A programmable function generator, which is suitable for construction in integrated circuit form, includes a current ladder which produces an output voltage or current which is a programmable function of an input voltage or current at n evenly spaced values of the input voltage or current corresponding to n spaced output points along the current ladder. Accurately controlled current sources or current drivers control the flow of currents to each of the n points and the flow of current from terminals of said current ladder including compensated current drivers, one of which differentially controls current flow from end terminals of the current ladder in response to a variable input control voltage or current which, for example, may be a linear ramp of voltage or current.